I don't want to provoke you any further, but I have been a member of this group for a long time and a baker (especially cake) for even longer.
People have been giving you the information you seek, you just aren't seeing it. There is nothing wrong with experimenting using a tried and true recipe to start and going from there. In fact, in culinary school that is exactly how we learned. we were taught the basics and only when we understood them were we free to try out different flavours and textures.
I don't see any advice I can give you beyond what you have gotten already. It would be nice to see/hear what your results are.
As for your pineapple cupcakes, I would check out the recipe link you were given and compare it to your attempt. I think you will find your answer quite quickly